排序方式： 共有75条查询结果，搜索用时 15 毫秒
21.
迄今为止，非撞击型超高压变质作用均发生在陆陆碰－撞造山带，这在东半球许多地点已被证实，超高压变质岩石以含柯石英和金刚石包体的榴辉岩和榴辉岩相变质岩石为代表，形成的温压环境为650－800℃，2.6-3.5GPa，研究证明大多数超高压岩石原是陆壳火山－沉积岩系，因此推断大陆深俯冲作用曾经发生，而超高压岩石现今又出露地表或浅表，意味着它们又从深部折返至地表，陆壳岩石深储冲和折返机制已成为大陆动力学研究的热点，但认识莫衷一是，争论的焦点是陆壳俯冲的深度到底多大可以形成超高压岩石？是什么机制使其发生深俯冲而又折返到浅表？本文通过世界上出露规模最大的超高压变质带－大别山碰撞过程的动力学分析，探讨非规则边界的碰撞引起的构造附加压力对超高压石形成的影响作用。模拟计算表明，大陆板块的早期碰撞，会引起碰撞附近的局部应力集中现象（平均压力较周围增大了5－9倍），构造压力在超高压中所占的比例约为20％－35％，由此推测，大别山高压－超高压岩石形成深度可能为65－80km。为此本文提出超高压岩石新成因模式－大陆点碰撞模式。这种模式符合力学基本原理，也符合地质记录和地质过程，可以解释为什么超高压岩石并非沿碰撞造山带全线存在，而是出现某些特定部位。本文提出喜马拉雅山撞带的东西犄角是典型的点碰撞区域，陆壳岩石的超高压变质作用均发生在这两个特定的部位。 相似文献
22.
ZHAO Wenzhi YANG Xiaoping Steve KERSHAW ZHANG Baomin 《《地质学报》英文版》2006,80(5):684-692
Lower Silurian mud mounds of the Shinuilan Formation, located in the southern Sichuan Basin, China, have developed in open shelf settings in deeper water than shallow-water reef-bearing limestones that occur in the region. An integration of the outcrop, drill data and seismic profiles show that contemporaneous faults have controlled the boundary and distribution of the sedimentary facies of Lower Silurian rocks in the southern Sichuan Basin. Mounds appear to have developed in the topographic lows formed by synsedimentary faulting, on the sheff of the Yangtze Platform. Average mound thickness is 20 m, maximum 35 m. Mounds are composed mainly of micrite, possibly microbially bound, and are overlain by shales. Mound tops are preferentially dolomitized, with the Mg^2＋ source probably from the clay content of the mound-top carbonate. Microfacies analysis and reconstruction of the diagenetic history reveal that the mound tops have higher porosity, and are gas targets; in contrast, mound cores and limbs show pores filled by three generations of calcite cement, and therefore have a low gas potential. 相似文献
23.
Crustal Structural and Tectonic Evolution and Oil Prospect Evaluation in the Songpan-Zoigê Block 
下载免费PDF全文
下载免费PDF全文 MA Yongsheng FU Xiaoyue WU Jingsheng CHEN Gao South Exploration Development Company Sinope Guanshang Kunming Yunnan Tongji University Siping Ro Shanghai China University of Geosciences Lumo Ro Wuhan Hubei 《《地质学报》英文版》2007,81(1):55-60
1 Introduction The Songpan-Zoigê Block (SRB) lies in the east of the Qinghai-Tibet Plateau. It is a triangle block confined and surrounded by three structure belts: the east Kunlun-west Qinling belt (EK-WQLB) to the north, the Sichuan Basin to the southeast and the Garzê-Litang-Jinsha River belt to the southwest. This block is also the joint part of three tectonic domains: the North China, South China and Qinghai-Tibet domains (Huang and Chen, 1987). The development and evolutio… 相似文献
24.
SUN Yuzhuang Basin Reservoir Research Centre University of Petroleum Shuiku Ro Changping Beijing JIN Yujie China University of Mining Technology Beijing 《《地质学报》英文版》2000,74(1):93-101
Previous studies have shown that the oxidizing brines from the Early Permian Rotliegende sequence have influences on the organic matter of Kupferschiefer. However, inside the Rotliegende sequence there are two other black shales: the Lower and Upper Antracosia shales, which have not been studied as much in detail as in Kupferschiefer. In the present study 12 samples from the Lower and Upper Antracosia shales were analyzed by organic geochemical methods in order to clarify the influences of the oxidizing brines on organic matter. The results indicate that the organic matter of the samples from the Upper Antracosia shale and the bottom of the Lower Antracosia shale was oxidized under the influences of the oxidizing brines. The oxidation resulted in a depletion of saturated hydrocarbons and the alky Is of the aromatic compounds. 相似文献
25.
YUAN Zhongxin BAI Ge Institute of Mineral Deposits Chinese Academy of Geological Sciences Baiwanzhuang Rd. Beijing ZHANG Zongqing Institute of Geology Chinese Academy of Geological Sciences Baiwanzhuang Rd. Beijing 《《地质学报》英文版》2000,74(2):148-153
Trachytic rock and its altered rock-fenite-in the Bayan Obo ore district, Inner Mongolia, China, were referred to as slate or feldspar rock before, and identified by the authors for the first time (in 1992). In the paper the mineral assemblages, structures and textures and petrochemical compositions of the rocks, as well as the electron microprobe analysis of feldspars in the rocks are described. The Sm-Nd isochron age of the trachytic rock is 1096±56 Ma, with INd=0.51100+4 (2σ) and εNd(t)= -4.4±0.7. Alterations of the trachytic rock, including microclinization, riebeckitization, aegirinization and biotitization, and accompanied rare element and REE mineralizations are discussed. Based on the occurrence of the trachytic rock and associated fenitization it is deduced that the Bayan Obo Fe-Nb-REE ore deposit is genetically related to magmatic-hydrothermal activity of an alkali carbonatite complex. 相似文献
26.
Geochronology and Significance of Granites Associated with Gold Deposits in the Jidong Area, China 总被引：1，自引：0，他引：1
The Jidong area is located on the north margin of the North China craton. It is a nucleus composed of the oldest rocks in China. Precambrian metamorphic rocks with various Phanerozoic granitoids invaded are widespread. Gold deposits here have close spatial relations to granitoids. Some deposits occur within them and others in the outer zone of the contact belt of the intrusion, extending thousands of metres. There have been controversial views in regard to the relations of the deposits to the intrusions although traditional techniques have been used to date the intrusions. In order to solve such a problem, the SHRIMP technique was adopted to date the U-Pb ages of zircon collected from the Yuerya intrusion which hosts the large-sized Yuerya Au deposit and Qingshankou intrusion 2 km away from the Jinchangyu (larger-sized) Au deposit. Analysis shows that the ages of 175±1 Ma and 174±3 Ma for Yuerya intrusion and the age of 199±2 Ma for Qingshankou granite indicate the Early Yanshanian stage of the Meso- 相似文献
27.
JI Zhansheng YAO Jianxin JIN Xiaochi YANG Xiangning WANG Yizhao YANG Hailin WU Guichun Institute of Geology Chinese Academy of Geological Sciences Baiwangzhuang Ro Beijing Department of Earth Sciences Nanjing University Nanjing Jiangsu Geological Survey of Yunnan Yujiang Ro Yuxi Yunnan 《《地质学报》英文版》2004,78(6):1179-1184
The Rabeignathus bucaramangus fauna was recently found from the limestone beds of the top part of the elastics-dominated Dingjiazhai Formation in the Aluotian section, southern Baoshan Block, western Yunnan. With Rabeignathus bucaramangus as the dominant species, this fauna includes Rabeignathus bucaramangus (Rabe), Homeoiranognathus huecoensis (Ritter), Sweetognathus inomatus Ritter, Sweetognathus whitei (Rhodes), Mesogondolella cf. bisselli (Clark and Behnken) and a few of ramiform elements. The characteristies of the fauna suggest that it can be correlated with the upper part of the Sweetognathus whitei Zone and assigned to the Middle Artinskian. 相似文献
28.
Deep Tectonic Processes and Superaccumulation of Metals Related to Granitoids in the Nanling MetaUogenic Province,China 总被引：1，自引：0，他引：1
PEI Rongfu WANG Ping''an and PENG Cong Institute of Mineral Deposits CAGS Baiwanzhuang Rd. Beijing Institute of Geomechanics CAGS Beijing 《《地质学报》英文版》1999,73(2)
The Nanling region is an important nonferrous and rare metal metallogenic province in South China, in which most of the deposits are related to granitoids in genesis. It covers southern Hunan, southern Jiangxi, Guangxi, Guangdong and Fujian provinces, with a total area of about 550,000 km2. This metallogenic province is well known in the world for its rich tungsten and tin resources. In the past 40-odd years, a vast amount of mineral exploration activities and studies of the geology of mineral deposits have been carried out and great achievements obtained in the province. This paper is focused on a discussion about the deep tectonic processes in the orogenic belt during the Mesozoic and their contribution to the superaccumulation of metals. Tectonically, this metallogenic province is composed of three units: (1) the marginal continental orogenic belt in the Southeastern Coast fold system in the Yanshanian; (2) the intercontinental orogenic belt in the collision suture belt between the Yangtze and Cathay 相似文献
29.
High- and Ultrahigh-pressure Metamorphism and Retrogressive Textures of Gneiss in the Donghai Area——Evidence from gneisses in drillhole ZK2304 总被引：6，自引：1，他引：5
LIU Fulai XU Zhiqin XU Huifen YANG Jingsui Institute of Geology CAGS Baiwanzhuang Rd. Beijing Zhu Xiling 《《地质学报》英文版》1999,73(3)
In the gneisses from the drillhole ZK2304 of the Donghai area, there have been preserved high- and ultrahigh-pressure metamorphic mineral assemblages, a series of complicated retrogressive textures and relevant metamorphic reactions. In addition to garnet, jadeititic-clinopyroxene and rutile, other peak stage (M2) minerals in some gneisses include phengite, aragonite and coesite or quartz pseudomorphs after coesite. The typical peak-stage mineral assemblages in gneisses are characterized by garnet + jadeitic-clinopyroxene + rutile + coesite, garnet + jadeitic-clinopyroxene + phengite + rutile ± coesite and garnet + jadeitic-clinopyroxene + aragonite + rutile ± coesite. The grossular content (Gro) in garnet is high and may reach 50. 1 mol%. The SiO2 content of phengite ranges from 54.37% to 54.84% with 3.54-3.57 p.f.u. Quartz pseudomorphs after coesite occur as inclusions in garnet.The gneisses of the Donghai area have been subjected to multistage recrystallization and exhibit a closewise P-T evolution 相似文献
30.
MA Tuhu ZHU Xingsheng LI Changjiang Institute of Geology Mineral Resources of Zhejiang Province Tiyuchang Ro Hangzhou 《《地质学报》英文版》1998,72(4):392-398
In this paper a nonlinear dynamic model for the distribution of element content and mineralization in the crust is suggested and the iteration relationship formula of this model coincides with the logistic equation. This shows that mineralization related with migration and enrichment of elements is in chaos, thus resulting in fractal structures of element content and ore reserves and their spatial distribution in the crust. 相似文献